I How feasible is home radio astronomy?

[sophiecentaur]

@Baluncore
There are many opportunities to scan along a line of constant altitude. A nautical almanac would help to find an appropriate altitude to coincide with an object of interest. Tracking would not be a prime requirement for a very interesting and worthwhile study.
To sum up, the electronics can produce a good SNR for spectral lines with a receiver right at the focus. Cheap. No tracking is needed on an entry level mount.

Some successful measurements are possible enough to justify more of the family budget being spent on more RA. That’s precisely the excuse for spending more and more money on the optical stuff. Most amateur astronomers will acknowledge that.

You really can’t knock low cost RA just because you’ve done big boys’ RA.

 

[Baluncore]

To sum up, the electronics can produce a good SNR for spectral lines with a receiver right at the focus. Cheap. No tracking is needed on an entry level mount.

It is good that you are now recognising that the receiver front-end needs to be at the focus. I agree that if you pull back your expectations sufficiently, then you may achieve your objective, within your budget. I would question whether the objective is worth the investment, or maybe you are just wanting to play. Ask yourself, why do you need to do RA?

You really can’t knock low cost RA just because you’ve done big boys’ RA.

I do not. I have the experience to recognise cases of Dunning-Kruger, where beginners are walking themselves into a complex trap. Education is the only counter to that behaviour. More can be learned by studying RA theory than by trying to do practical RA on a budget. I apologise if education dashes their dreams.
Take a look at my avatar; "The Bird of Self-Knowledge". The subtitle could be: "Don't be a goose, by allowing your dreams to lead you by the nose".

 

[sophiecentaur]

It is good that you are now recognising that the receiver front-end needs to be at the focus.

I never denied that; did someone else deny it?. Every home satellite dish has the vital stuff done at the focus.

. I agree that if you pull back your expectations sufficiently, then you may achieve your objective, within your budget

That's the whole basis of successful engineering. Expectations need to be controlled in all self funded ventures. Suppliers and well established amateur astronomers are to blame for many beginners shelling out far too much on a new hobby. It's a great shame that kids are just not attracted to learn astronomy from the bottom up. The plug and play systems start at prices that are just affordable by doting parents but £500+ is often totally wasted when a pair of £50 binoculars will suffice ash a way in. It's true that RA doesn't produce such enchanting results as you get with a cheap pair of optical bins but cost restraints never affect the quality of experience when you start.

How would we know anything about the Cosmos if pre-telescope skywatching and measuring had not been attempted.

Ask yourself, why do you need to do RA?

That's a universal question. Just pointing your antenna to an area of bright blue sky can reveal the presence of an object that could only be seen at night in six months' time. If that's not a turn-on for an Engineer then I wonder what is.

 

[Baluncore]

There are many opportunities to scan along a line of constant altitude. A nautical almanac would help to find an appropriate altitude to coincide with an object of interest. Tracking would not be a prime requirement for a very interesting and worthwhile study.

Given the RA, Dec of a source, a fixed EW array of two or more elements could be constructed with that declination. That array would observe the source for some period each day, as it was swept by the beam width of the elements. Deconvoluting the combined signal, by the array pattern, would give a good representation of the source. Now we need an element that could be repeated, and a source with sufficient flux at some wavelength, to be imaged. Conceptually it is simple, but do you have any suggestions of practical targets that might be observed by home radio astronomers?

To sum up, the electronics can produce a good SNR for spectral lines with a receiver right at the focus. Cheap. No tracking is needed on an entry level mount.

You refer to spectral lines. Apart from hydrogen at 1420 MHz, what spectral lines are emitted by objects with sufficient flux to be imaged by such a home system? Does that class of observable objects, have any members?